You do have to have provided all the info as if you were going to deposit, but do not have to deposit. They need to know your address, in case you do win.
The FT freerolls, especially the Holdem FR's fill remarkably fast. The last HoldEm of the day will fill in 30 seconds, sometimes less. The Horse, Omaha, and Razz fr's take a few minutes, depending on the day of the week. You can not treat signups there at a leisurely pace. You MUST be right there ready to hit the register button when it appears.